Model selection method and device for screw type water chilling unit and computer readable storage medium

Abstract

The invention relates to the technical field of water chilling unit design and model selection, and discloses a model selection method and device for a screw type water chilling unit and a computer readable storage medium, and the model selection method for the screw type water chilling unit comprises the steps that the nominal refrigerating capacity Qnom and the load rate LOAD% are obtained; according to the nominal refrigerating capacity Qnom and the load rate LOAD%, the target refrigerating capacity Q of the unit is determined; the maximum refrigerating capacity Qmax and the minimum refrigerating capacity Qmin of the unit are determined; according to the target refrigerating capacity Q, the maximum refrigerating capacity Qmax and the minimum refrigerating capacity Qmin, operation parameters, corresponding to the load rate LOAD%, of a compressor of the unit are determined; and according to the operation parameters, the output refrigerating capacity Qt, corresponding to the load rate LOAD%, of the unit is determined. The simulation calculation of the water chilling unit is carried out by updating different load rates LOAD%, the operation performance parameters of the multiple sets of water chilling units can be obtained, the better performance parameters of the screw type water chilling unit can be obtained through the multiple sets of performance parameters, and the performance output of the screw type water chilling unit in the actual application process is improved.

Description

Technical Field

[0001] The present application relates to the technical field of the design and selection of chillers, for example, to a method and device for selecting a screw chiller, and a computer-readable storage medium. Background Art

[0002] Limited by the high production cost and long production and testing cycle of screw chillers, it is impossible to achieve the performance differences caused by each technical optimization or technical change of the chiller through the production prototype test. In addition, with the popularization of high-efficiency and energy-saving computer rooms, the partial load performance of the chilled water host is increasingly valued during the computer room design stage, and a large amount of partial load performance data is required to calculate the overall performance of the computer room.

[0003] The air conditioner selection method disclosed in the related art performs air conditioner simulation calculations through a heat exchange device simulation calculation system and a compressor simulation calculation system and according to the air conditioner selection input parameters; determines whether to stop the calculation according to the stop calculation condition and the air conditioner simulation calculation result: if so, determines the air conditioner selection result according to the air conditioner selection input parameters. Among them, the heat exchange device simulation calculation system and the compressor simulation calculation system perform data communication through an Excel VBA program.

[0004] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:

[0005] In the related art, the air conditioner selection method based on the Excel VBA program is limited by the running speed of the Excel VBA program and has poor compatibility. When calculating the partial load of a multi-compressor unit, it can only calculate the performance of the preset compressor combination, thereby affecting the performance output during actual application.

[0006] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0007] To have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a general review, nor is it intended to identify key / important constituent elements or delineate the protection scope of these embodiments, but rather serves as a preface to the subsequent detailed description.

[0008] The embodiments of the present disclosure provide a method and device for selecting a screw chiller, and a computer-readable storage medium, to optimize the accuracy of the selection of a screw chiller.

[0009] In some embodiments, a method for selecting a screw chiller is provided, including: obtaining the nominal refrigerating capacity Qnom and the load rate LOAD%; according to the nominal refrigerating capacity Q nom and the load rate LOAD%, determine the target refrigerating capacity Q of the unit; determine the maximum refrigerating capacity Q of the unit max and the minimum refrigerating capacity Q min ; according to the target refrigerating capacity Q and the maximum refrigerating capacity Q max and the minimum refrigerating capacity Q min , determine the operating parameters of the compressor of the unit corresponding to the load rate LOAD%; according to the operating parameters, determine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% t .

[0010] In some embodiments, a selection device for a screw water chiller is provided, including a processor and a memory storing program instructions, and the processor is configured to execute the selection method for the screw water chiller as described in the above embodiments when running the program instructions.

[0011] In some embodiments, a computer-readable storage medium is provided, storing program instructions, and the program instructions are used to cause a computer to execute the selection method for the screw water chiller as described in the above embodiments when running.

[0012] The selection method, device and computer-readable storage medium for the screw water chiller provided by the embodiments of the present disclosure can achieve the following technical effects:

[0013] The selection method for the screw water chiller provided by the present disclosure performs simulation calculations on the water chiller for different load rates LOAD%. Specifically, through the nominal refrigerating capacity Q nom and the load rate LOAD%, determine the target refrigerating capacity Q of the unit, and according to the target refrigerating capacity Q and the maximum refrigerating capacity Q max and the minimum refrigerating capacity Q min , determine the operating parameters of the compressor of the unit corresponding to the load rate LOAD%. Then, according to the operating parameters, determine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% t . In this way, by updating the simulation calculations of the water chiller for different load rates LOAD%, multiple sets of performance parameters of the water chiller operation can be obtained, and relatively optimal performance parameters of the screw water chiller can be obtained through multiple sets of performance parameters. Compared with the related art that can only calculate the performance of the preset compressor combinations, the present disclosure can improve the performance output of the screw water chiller in actual applications.

[0014] The above general description and the following description are only exemplary and explanatory, and are not used to limit this application. Description of the Drawings

[0015] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and wherein:

[0016] Figure 1 is a schematic diagram of a method for selecting a screw chiller provided by an embodiment of the present disclosure;

[0017] Figure 2 is a schematic diagram of a method for selecting a screw chiller provided by an embodiment of the present disclosure;

[0018] Figure 3 is a schematic diagram of a method for selecting a screw chiller provided by an embodiment of the present disclosure;

[0019] Figure 4 is a schematic diagram of a method for selecting a screw chiller provided by an embodiment of the present disclosure;

[0020] Figure 5 is a schematic diagram of a method for selecting a screw chiller provided by an embodiment of the present disclosure;

[0021] Figure 6 is a structural block diagram of a device for selecting a screw chiller provided by an embodiment of the present disclosure. Detailed Embodiments

[0022] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the drawings. The attached drawings are for reference and illustration only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other instances, well-known structures and devices may be shown in a simplified manner.

[0023] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data may be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0024] Unless otherwise specified, the term "plurality" means two or more.

[0025] In the embodiments of the present disclosure, the character " / " indicates an "or" relationship between the front and rear objects. For example, A / B means: A or B.

[0026] The term "and / or" is an associative relationship describing an object, indicating that three relationships can exist. For example, A and / or B means: A or B, or the three relationships of A and B.

[0027] The term "corresponding" can refer to an associative relationship or a binding relationship. A corresponding to B means that there is an associative relationship or a binding relationship between A and B.

[0028] In some embodiments, the screw chiller has multiple compressor combination forms. It can include only one compressor or multiple compressors. The implementation method of the unit's part-load operation is different according to the type of the chiller. The screw chiller includes a variable-frequency screw chiller and a fixed-frequency screw chiller.

[0029] Among them, the refrigerating capacity adjustment principle of the variable-frequency screw chiller is as follows: The variable-frequency screw compressor changes the refrigerating capacity of the compressor by changing the power supply frequency and then changing the compressor speed. The higher the frequency, the higher the speed, and the greater the refrigerating capacity. Usually, each model of compressor has a preset frequency adjustment range, that is, there are upper and lower frequency limits. These information are built into the software. When calculating, the corresponding maximum or minimum frequency is obtained and calculated to get the maximum or minimum refrigerating capacity of the compressor.

[0030] The refrigerating capacity adjustment principle of the fixed-frequency screw chiller is as follows: The fixed-frequency screw compressor cannot change the refrigerating capacity (i.e., capacity change) of the compressor by changing the speed. It can only adjust the capacity by adjusting the slide valve, which is called capacity adjustment. Its principle is to use the oil pressure piston to push the capacity adjustment slide valve. When in partial load, the capacity adjustment slide valve moves to bypass part of the refrigerant gas back to the suction end, reducing the refrigerant gas flow rate in the circuit to reduce the refrigerating capacity, so as to achieve the partial load function. When shutting down, the force of the spring makes the piston return to the starting state. The range from the starting position to the end position of the slide valve is called the "capacity adjustment range", and the capacity adjustment range is 0≤CI≤1. The position of the slide valve at a certain point is called the "capacity adjustment state CI". When the capacity adjustment state CI = 1, the position of the slide valve makes no refrigerant gas bypass back to the suction end, and the refrigerating capacity is the largest. The smaller the value of the capacity adjustment state CI, the more refrigerant gas bypasses back to the suction end, and the smaller the refrigerating capacity. Therefore, when calculating the maximum refrigerating capacity, the capacity adjustment state of the compressor is set to 1. When calculating the 10% to 100% partial load, the capacity adjustment state of the compressor needs to be adjusted between 0 and 1. For different loads, a capacity adjustment state of the compressor needs to be given, and the partial load calculation is realized by restricting the capacity adjustment state of the compressor.

[0031] Generally, the lower limit of the capacity adjustment state of a compressor varies according to the characteristics of each compressor. Therefore, the lower limit value CI of the capacity adjustment state of compressors of different models min is different. The lower limit value of the capacity adjustment state of compressors of different models is built into the software, and the corresponding minimum capacity adjustment value CI is retrieved during calculation min and substituted to obtain the minimum refrigerating capacity of the compressor.

[0032] In some embodiments, a screw chiller includes multiple compressors. Then, the definitions of the maximum refrigerating capacity and the minimum refrigerating capacity of the screw chiller are as follows: Q min is the minimum refrigerating capacity of the unit, and Q max is the maximum refrigerating capacity of the unit. The minimum refrigerating capacity of a single compressor is Q min i , where i = 1, 2, …, N, and the maximum refrigerating capacity of a single compressor is Q max i , where i = 1, 2, …, N. Here, N is the total number of compressors of the screw chiller, and N is a positive integer.

[0033] Taking the example that the unit includes 3 compressors, the minimum refrigerating capacity Q min = sum(Q min 1 , Q min 2 , Q min 3 ). After shutting down 1 unit, Q min = sum(Q min 1 , Q min 2 ). After shutting down 2 units, Q min = Q min 1 . Q max = sum(Q max 1 , Q max 2 , Q max 3 ). After shutting down 1 unit, Q max = sum(Q max 1 , Q max 2 ). After shutting down 2 units, Q max = Q max 1 .

[0034] In some embodiments, a screw chiller includes 1 compressor. Then, the maximum refrigerating capacity Q maxis the maximum refrigerating capacity of the compressor, and Q is the minimum refrigerating capacity of the screw water chiller min is the minimum refrigerating capacity of the compressor.

[0035] In some embodiments, a selection device for a screw water chiller is provided, including a processor and a memory storing program instructions. The processor is configured to execute the selection method for the screw water chiller when running the program instructions.

[0036] Optionally, the selection method for the screw water chiller runs based on the C# software platform, realizes docking with the database of the screw compressor, and is used to simulate and calculate the part-load performance of the screw water chiller to obtain the performance parameters of the unit.

[0037] In some embodiments, in combination with Figure 1 as shown, a selection method for a screw water chiller is provided, including:

[0038] S101, the processor obtains the rated refrigerating capacity Q nom and the load rate LOAD%.

[0039] S102, the processor determines the target refrigerating capacity Q of the unit according to the rated refrigerating capacity Q nom and the load rate LOAD%.

[0040] S103, the processor determines the maximum refrigerating capacity Q max and the minimum refrigerating capacity Q min .

[0041] S104, the processor determines the operating parameters of the compressor of the unit corresponding to the load rate LOAD% according to the target refrigerating capacity Q and the maximum refrigerating capacity Q max , the minimum refrigerating capacity Q min .

[0042] S105, the processor determines the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameters t .

[0043] The selection method for the screw water chiller provided by the present disclosure performs simulation calculations on the water chiller for different load rates LOAD%. Specifically, through the rated refrigerating capacity Q nom and the load rate LOAD%, the target refrigerating capacity Q of the unit is determined, and according to the target refrigerating capacity Q and the maximum refrigerating capacity Q max , the minimum refrigerating capacity Q min , the operating parameters of the compressor of the unit corresponding to the load rate LOAD% are determined. Then, according to the operating parameters, the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% is determined tIn this way, by updating different load rates LOAD%, the simulation calculation of the chiller can be carried out, and the performance parameters of the chiller operation can be obtained. And through multiple groups of performance parameters, the optimal performance parameters of the screw chiller can be obtained. Compared with the related technology that can only calculate the performance of the preset compressor combination, the present disclosure can improve the performance output of the screw chiller in actual application.

[0044] Optionally, according to the target refrigerating capacity Q and the maximum refrigerating capacity Q max , the minimum refrigerating capacity Q min , the steps of determining the operating parameters of the compressor of the unit corresponding to the load rate LOAD% include: when Q max ≤Q, then determine the operating parameters of the compressor as the maximum value of the target parameters. When Q < Q max , then according to Q min and the number n of the compressors in the operating state, determine the operating parameters of the compressor. Wherein, the target parameters include the operating frequency or the capacity modulation state.

[0045] In this embodiment, the target refrigerating capacity Q is compared with the maximum refrigerating capacity Q max to determine the operating parameters of the compressor of the unit corresponding to the load rate LOAD% according to the comparison result.

[0046] When Q max ≤Q, that is, the target refrigerating capacity Q exceeds the maximum refrigerating capacity Q max of the unit, then determine the operating parameters of the compressor as the maximum value of the target parameters.

[0047] When Q < Q max , that is, the target refrigerating capacity Q does not exceed the maximum refrigerating capacity Q max of the unit. Further, the target refrigerating capacity Q is compared with the minimum refrigerating capacity Q min of the unit. According to the comparison result of Q and Q min , and the number n of the compressors in the current operating state, further determine the operating parameters of the compressor. By determining the number of the compressors in the operating state, it is determined whether the current partial load of the unit reaches the lower limit of the partial load of the unit, so as to improve the accuracy of the calculation of the performance parameters of the unit and the comprehensiveness of the covered operating conditions.

[0048] Wherein, when the screw chiller is a variable-frequency screw chiller, the operating parameter of the unit is the operating frequency. That is, when Q max ≤Q, then determine the operating frequency F of the compressor as the maximum value F max of the compressor operating frequency. When Q < Q max , then according to Q minBased on the nominal cooling capacity Q and the number n of compressors in the operating state, determine the operating frequency F of the compressor.

[0049] When the screw chiller is a fixed-frequency screw chiller, the operating parameter of the unit is the capacity modulation state. That is, when Q max ≤Q, then determine that the capacity modulation state CI of the compressor is the maximum value CI max of the compression capacity modulation state, CI max = 1. When Q < Q max , then according to Q min and the number n of compressors in the operating state, determine the capacity modulation state CI of the compressor.

[0050] In some embodiments, as shown in Figure 2 , a selection method for a screw chiller is provided. The number of compressors in the screw chiller is 1, and the selection method includes:

[0051] S201, the processor obtains the nominal cooling capacity Q nom and the load rate LOAD%.

[0052] Optionally, input the nominal cooling capacity Q nom of the chiller and the load rate LOAD% participating in the calculation. Among them, the load rate LOAD% participating in each calculation takes different values to calculate the target cooling capacity Q corresponding to different load rates LOAD%.

[0053] S202, the processor determines the target cooling capacity Q of the unit according to the nominal cooling capacity Q nom and the load rate LOAD%.

[0054] Optionally, the target cooling capacity Q = Q nom ×LOAD%.

[0055] S203, the processor determines the maximum cooling capacity Q max and the minimum cooling capacity Q min of the unit.

[0056] Among them, the maximum cooling capacity Q max of the screw chiller is the maximum cooling capacity of the compressor, and the minimum cooling capacity Q min of the screw chiller is the minimum cooling capacity of the compressor.

[0057] S204, the processor determines whether Q is greater than or equal to Q max . If the result is yes, go to S205. If the result is no, go to S206.

[0058] S205, when Q max ≤Q, the processor determines that the operating parameter of the compressor is the maximum value of the target parameter.

[0059] S206, the processor determines whether Q is greater than or equal to Q min . If the result is yes, go to S207. If the result is no, go to S208.

[0060] S207, the processor determines the operating parameter of the compressor as the product of the maximum value of the target parameter and Q when min ≤Q<Q max , where Q b =Q / Q b max .

[0061] S208, the processor determines the operating parameter of the compressor as the minimum value of the target parameter when Q<Q min .

[0062] S209, the processor determines the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameter t .

[0063] In this embodiment, the screw chiller includes 1 compressor. When Q<Q max , that is, the target refrigerating capacity Q does not exceed the maximum refrigerating capacity Q of the compressor max , further, compare the target refrigerating capacity Q with the minimum refrigerating capacity Q of the compressor min . When Q min ≤Q<Q max , determine the operating parameter of the compressor as the product of the maximum value of the target parameter and Q b , Q b =Q / Q max . When Q<Q min , determine the operating parameter of the compressor as the minimum value of the target parameter.

[0064] Among them, when the screw chiller is a variable-frequency screw chiller and includes 1 compressor, the operating parameter of the unit is the operating frequency of the compressor. That is, when Q max ≤Q, determine the operating frequency F of the compressor as the maximum value F of the compressor operating frequency max . When Q min ≤Q<Q max , the operating frequency F = F max ×(Q / Q max ). When Q<Q min , determine the operating frequency F of the compressor as F of the compressor operating frequency min .

[0065] ​When the screw chiller is a fixed-frequency screw chiller and includes one compressor, the operating parameters of the chiller are in the capacity modulation state. That is, when Q max ≤Q, the capacity modulation state CI of the compressor is determined to be the maximum value CI max of the compression capacity modulation state, and CI max = 1. When Q min ≤Q < Q max , the capacity modulation state CI of the compressor is determined to be CI = Q / Q max . When Q < Q min , the CI of the compressor is determined to be the minimum value CI min of the capacity modulation state of the compressor. Further, according to the determined operating frequency F or capacity modulation state CI, relevant data is called from the database of the compressor for calculation to obtain the output cooling capacity Q t of the chiller corresponding to the load rate LOAD%. Among them, the database of the compressor can be the parameter database of the compressor provided by the compressor manufacturer.

[0066] In some embodiments, as shown in Figure 3 , a selection method for a screw chiller is provided. The number of compressors of the screw chiller is one, and the selection method includes:

[0067] S301, the processor obtains the nominal cooling capacity Q nom and the load rate LOAD%.

[0068] Optionally, the nominal cooling capacity Qnom of the chiller and the load rate LOAD% participating in the calculation are input. Among them, the value of the load rate LOAD% participating in each calculation is different to calculate the target cooling capacity Q corresponding to different load rates LOAD%.

[0069] S302, the processor determines the target cooling capacity Q nom of the chiller according to the nominal cooling capacity Q

[0070] Optionally, the target cooling capacity Q = Q nom ×LOAD%.

[0071] S303, the processor determines the maximum cooling capacity Q max and the minimum cooling capacity Q min of the chiller.

[0072] Among them, the maximum cooling capacity Q max of the screw chiller is the maximum cooling capacity of the compressor, and the minimum cooling capacity Q min of the screw chiller is the minimum cooling capacity of the compressor.

[0073] S304, the processor determines whether Q is greater than or equal to Q max . If the result is yes, it proceeds to S305. If the result is no, it proceeds to S307.

[0074] S305, the processor determines the operating parameter of the compressor as the maximum value of the target parameter when Q max ≤Q.

[0075] S306, the processor determines whether Q is greater than or equal to Q min . If the result is yes, it proceeds to S307. If the result is no, it proceeds to S313.

[0076] S307, the processor determines the operating parameter of the compressor as: the product of the maximum value of the target parameter and Q min when Q max ≤Q < Q b , where Q b = Q / Q max .

[0077] S308, the processor determines the output cooling capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameter t .

[0078] S309, the processor determines the ratio of the absolute value of the difference between Q t and Q to Q.

[0079] S310, the processor determines whether the ratio is less than or equal to the ratio threshold. If the result is yes, it proceeds to S311. If the result is no, it proceeds to S312.

[0080] S311, the processor determines the performance parameter of the unit according to the output cooling capacity Q t and the database of the compressor, and outputs it.

[0081] S312, the processor adjusts the operating parameter according to the preset formula and returns to S308.

[0082] S313, the processor determines the operating parameter of the compressor as the minimum value of the target parameter when Q < Q min .

[0083] S314, the processor determines the performance parameter of the unit corresponding to the load rate LOAD% according to the operating parameter.

[0084] In this embodiment, when Q min ≤Q < Q max , the operating parameter of the compressor is determined as: the product of the maximum value of the target parameter and Q b , where Q b = Q / Q maxDetermine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameters. t Then, utilize the obtained output refrigerating capacity Q of the unit. t Compare with the target refrigerating capacity Q to determine whether the operating parameters meet the requirements.

[0085] Specifically, calculate the ratio X of the absolute value of the difference between Q t and Q to Q. When X is less than or equal to the ratio threshold, it indicates that the operating parameters meet the requirements. Then, according to the operating parameters, retrieve the relevant parameters in the database of the compressor to determine the performance parameters of the unit. When X is greater than the ratio threshold, it indicates that there are deviations in the operating parameters. According to the preset formula, adjust the operating parameters. And according to the adjusted operating parameters, re-determine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD%. t In this way, the accuracy of unit selection is improved.

[0086] Optionally, the value range of the ratio threshold is from 0.08% to 0.15%. Specifically, the value of the ratio threshold is 0.08%, 0.1%, or 0.15%.

[0087] In some embodiments, the steps of determining the operating parameters of the compressor according to Q min and the number n of compressors in the operating state include: when n≥2 and Q<Q min , control one of the n compressors to shut down, and update the minimum refrigerating capacity Q of the unit. min According to the updated Q min and the updated n, determine the operating parameters of the compressor.

[0088] In this embodiment, when the chiller includes multiple compressors, when the operating parameter of one compressor reaches the lower limit, the operating parameters of other compressors can continue to be reduced. When all compressors reach the lower limit, one or several compressors can be stopped to achieve further load reduction until only one compressor remains and its operating parameter also reaches the lower limit and cannot be adjusted anymore. Through the embodiments of the present disclosure, multiple sets of performance parameters of the unit can be obtained for different numbers of compressors in the operating state, thereby improving the optimization of the unit selection result.

[0089] In some embodiments, the steps of determining the operating parameters of the compressor according to Q min and the number n of compressors in the operating state include: when n≥2 and Q min ≤Q<Q max , determine the ratio of the absolute value of the difference between Q t and Q to Q. When the ratio is less than the ratio threshold and Q<Q maxIn the case of, save according to Q t , determine the performance parameters of the unit corresponding to the load rate LOAD%. And control one of the n compressors to shut down, and update Q max . And according to the updated Q max , update the operating parameters of the compressor. When the ratio is less than the ratio threshold and Q≥Q max , output the performance parameters of the unit corresponding to the load rate LOAD% determined according to Q t . When the ratio is greater than the ratio threshold, adjust the operating parameters. According to the adjusted operating parameters, update Q t .

[0090] In this embodiment, when the chiller includes multiple compressors, when the operating parameter of one compressor reaches the lower limit, the operating parameters of other compressors can continue to be reduced. When all compressors reach the lower limit, one or several compressors can be stopped to further reduce the load until only one compressor remains and its operating parameter also reaches the lower limit and cannot be adjusted anymore. Through the embodiments of the present disclosure, by simulating and calculating the performance of the unit according to the operating parameters of different numbers of compressors in the operating state, multiple sets of operating performance parameters of the unit can be obtained, and then the optimal set of performance parameters can be obtained from the multiple sets of operating parameters of the unit to improve the optimization of the unit selection result.

[0091] Furthermore, when Q min ≤Q<Q max , use the obtained output cooling capacity Q t of the unit and the target cooling capacity Q to determine whether the operating parameters meet the requirements. Specifically, calculate the ratio X of the absolute value of the difference between Q t and Q to Q, When X is less than the ratio threshold, it means that the operating parameters meet the requirements, then according to the operating parameters, retrieve the relevant parameters in the database of the compressor to determine the performance parameters of the unit. When X is greater than or equal to the ratio threshold, it means that there is a deviation in the operating parameters, and according to the preset formula, adjust the operating parameters. And according to the adjusted operating parameters, re-determine the output cooling capacity Q t of the unit corresponding to the load rate LOAD%. In this way, the accuracy of unit selection is improved.

[0092] In some embodiments, as shown in Figure 4 , a method for selecting a screw chiller is provided. The number of compressors of the screw chiller is N, and N is a positive integer greater than 1. The selection method includes:

[0093] S401, the processor obtains the nominal cooling capacity Q nom and the load rate LOAD%.

[0094] Optionally, the nominal refrigerating capacity Q of the input chiller nom , and the load rate LOAD% involved in the calculation. Among them, the value of the load rate LOAD% involved in each calculation is different to calculate the target refrigerating capacity Q corresponding to different load rates LOAD%.

[0095] S402. The processor determines the target refrigerating capacity Q of the unit according to the nominal refrigerating capacity Q nom and the load rate LOAD%.

[0096] Optionally, the target refrigerating capacity Q = Q nom ×LOAD%.

[0097] S403. The processor determines the maximum refrigerating capacity Q max and the minimum refrigerating capacity Q min of the unit.

[0098] In the case where the unit includes multiple compressors, the maximum refrigerating capacity Q max is equal to the sum of the maximum refrigerating capacities of multiple compressors, and the minimum refrigerating capacity Q min of the unit is equal to the sum of the minimum refrigerating capacities of multiple compressors.

[0099] S404. The processor determines whether Q is greater than or equal to Q max . If the result is yes, go to S405. If the result is no, go to S406.

[0100] S405. When Q max ≤Q, the processor determines that the operating parameter of the compressor is the maximum value of the target parameter.

[0101] S406. The processor determines whether Q is greater than or equal to Q min . If the result is yes, go to S407. If the result is no, go to S416.

[0102] S407. When Q min ≤Q<Q max , the processor determines that the operating parameter of the compressor is: the product of the maximum value of the target parameter and Q b , where Q b = Q / Q max .

[0103] S408. The processor determines the output refrigerating capacity Q t of the unit corresponding to the load rate LOAD% according to the operating parameter.

[0104] S409. The processor determines the ratio of the absolute value of the difference between Q t and Q to Q.

[0105] Using the obtained output refrigerating capacity Q of the unit t and the target refrigerating capacity Q, determine whether the operating parameters meet the requirements. Specifically, calculate the ratio of the absolute value of the difference between Q t and Q to Q

[0106] S410, the processor determines whether the ratio is less than or equal to the ratio threshold. If the result is no, go to S411. If the result is yes, go to S412.

[0107] S411, the processor adjusts the operating parameters according to a preset formula and returns to S408.

[0108] When X is greater than the ratio threshold, it indicates that there is a deviation in the operating parameters. According to the preset formula, adjust the operating parameters. And according to the adjusted operating parameters, re-determine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% t . In this way, the accuracy of unit selection is improved.

[0109] S412, the processor determines whether Q is less than Q max . If the result is yes, go to S413. If the result is no, go to S418.

[0110] S413, the processor saves the performance parameters of the unit corresponding to the load rate LOAD% determined according to Q max when the ratio is less than or equal to the ratio threshold and Q < Q t .

[0111] When X is less than or equal to the ratio threshold and Q < Q max , it indicates that the operating parameters meet the requirements. Then, according to the operating parameters, retrieve the relevant parameters in the database of the compressor, determine the performance parameters of the unit, and save this set of performance parameters.

[0112] S414, the processor determines the number n of compressors in the operating state.

[0113] S415, the processor determines whether n is less than 2. If the result is yes, go to step S416. If the result is no, go to step S417.

[0114] S416, the processor compares multiple sets of stored performance parameters and extracts the optimal set of performance parameters from the multiple sets of performance parameters.

[0115] S417, the processor controls one of the n compressors to shut down and updates Q max , and returns to S407. S418, when the ratio is less than the ratio threshold and Q ≥ Q max , output according to Q t, the performance parameters of the unit corresponding to the determined load rate LOAD%.

[0116] S419, when Q < Q min , the processor controls one of the n compressors to shut down and updates the minimum refrigerating capacity Q of the unit min .

[0117] S420, the processor determines whether the updated Q min is less than or equal to Q. If the result is yes, go to S407; if the result is no, go to S421.

[0118] S421, the processor determines whether the number n of compressors in the running state is less than 2. If the result is yes, go to S422. If the result is no, go to S419.

[0119] S422, the processor determines that the operating parameters of the compressor are the minimum values of the target parameters.

[0120] S423, the processor determines the performance parameters of the unit corresponding to the load rate LOAD% according to the operating parameters.

[0121] In this embodiment, when the chiller includes multiple compressors, when the operating parameters of one compressor reach the lower limit, the operating parameters of other compressors can be further reduced. When all compressors reach the lower limit, one or several compressors can be stopped to achieve further reduction of the load until only one compressor remains and the operating parameters also reach the lower limit and cannot be adjusted anymore. Through the embodiments of the present disclosure, multiple sets of performance parameters of the unit can be obtained for different numbers of compressors in the running state, thereby improving the optimization of the unit selection result.

[0122] That is, taking the unit including 3 compressors as an example, through the solution provided by the present disclosure, for each LOAD%, the following 3 sets of performance parameters can be obtained, namely: the performance parameters when all 3 compressors are in the running state, the performance parameters when 2 compressors are in the running state, and the performance parameters when 1 compressor is in the running state.

[0123] In some embodiments, the screw chiller is a variable-frequency screw chiller, and the operating parameter is the operating frequency F, then the preset formula is: where F max is the maximum operating frequency of the compressor.

[0124] In some embodiments, the screw chiller is a fixed-frequency screw chiller, and the operating parameters are: the capacity modulation state CI, and the preset formula is:

[0125] Optionally, when the ratio is less than the ratio threshold and Q < Qmax In the case of, save according to Q t , after the step of determining the performance parameters of the unit corresponding to the load rate LOAD%, it further includes: updating the number of compressors in the operating state. In the case where the updated number is greater than or equal to 2, control one of the n compressors to shut down, and update Q max , return according to the operating parameters, determine the output cooling capacity Q of the unit corresponding to the load rate LOAD% t . In the case where the updated number is 1, compare the saved multiple sets of performance parameters, and output the optimal set of performance parameters among the multiple sets of performance parameters.

[0126] In some embodiments, in combination with Figure 5 as shown, a method for selecting a screw chiller is provided, including:

[0127] S501, the processor determines the combination set of load rates LOAD% participating in the calculation.

[0128] S502, the processor sequentially obtains the load rates LOAD% in the combination set according to the preset order.

[0129] S503, the processor determines the target cooling capacity Q of the unit according to the nominal cooling capacity Q nom and the load rate LOAD%.

[0130] S504, the processor determines the maximum cooling capacity Q of the unit max and the minimum cooling capacity Q min .

[0131] S505, the processor determines the operating parameters of the compressor of the unit corresponding to the load rate LOAD% according to the target cooling capacity Q and the maximum cooling capacity Q max and the minimum cooling capacity Q min .

[0132] S506, the processor determines the output cooling capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameters t .

[0133] In this embodiment, by sequentially obtaining the load rates LOAD% in the combination set according to the preset order, the performance parameters of the unit corresponding to multiple load rates LOAD% can be calculated, thereby improving the comprehensiveness and accuracy of the simulation calculation results of the unit, improving the selection accuracy of the chiller, and improving the energy efficiency in the actual use of the chiller.

[0134] Optionally, the step of determining a set of combinations of load rates LOAD% participating in the calculation includes: obtaining a plurality of load rates LOAD% at preset interval differences between 0 and 100%, to obtain a set of combinations including a plurality of load rates LOAD%.

[0135] In this embodiment, the load rate LOAD% is extracted at preset interval differences between 0 and 100%, so as to obtain a set of combinations including the load rate LOAD%.

[0136] Among them, the value range of the preset interval difference is 5% to 15%, and the specific values include but are not limited to: 5%, 10% or 15%.

[0137] Optionally, the preset order includes a plurality of load rates LOAD% from large to small, or from small to large.

[0138] Optionally, the compressor database includes but is not limited to: power, operating frequency or capacity modulation status, pressure, temperature, etc. The specific parameters can be directly called according to actual needs and will not be elaborated here.

[0139] Optionally, the performance parameters include but are not limited to: refrigerating capacity, power, energy efficiency ratio, part load performance coefficient. In the embodiment of the present application, referring to the working conditions specified in the national standard GB / T18430.1-2007 of the People's Republic of China, the integrated part load value IPLV (Integrated Part Load Value) and the non-standard part load value NPLV (No-standard Part Load Value) are calculated respectively. It should be noted that the embodiments of the present invention use the conventional IPLV calculation method and NPLV calculation method in the art to calculate IPLV and NPLV. For the sake of concise description, the calculation processes of IPLV and NPLV will not be specifically described here.

[0140] Combined with Figure 6 As shown, the embodiment of the present disclosure provides a selection device 60 for a screw chiller, including a processor 600 and a memory 601. Optionally, the device 60 may further include a communication interface 602 and a bus 603. Among them, the processor 600, the communication interface 602, and the memory 601 can complete mutual communication through the bus 603. The communication interface 602 can be used for information transmission. The processor 600 can call the logical instructions in the memory 601 to execute the selection method for the screw chiller in the above embodiment.

[0141] In addition, when the logical instructions in the above-mentioned memory 601 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0142] As a computer-readable storage medium, the memory 601 can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the methods in the embodiments of the present disclosure. The processor 600 executes functional applications and data processing by running the program instructions / modules stored in the memory 601, that is, implements the method for selecting a screw chiller in the above embodiments.

[0143] The memory 601 may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the terminal device, etc. In addition, the memory 601 may include high-speed random access memory and may also include non-volatile memory.

[0144] The embodiments of the present disclosure provide a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are configured to execute the above-mentioned method for selecting a screw chiller.

[0145] The technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the present disclosure. The foregoing storage medium may be a non-transitory storage medium, such as: a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc, etc., which are various media that can store program codes.

[0146] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. The embodiments only represent possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terms used in this application are only for describing the embodiments and do not limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, as used in this application, the term "and / or" refers to any and all possible combinations of one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" etc. mean the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups of these. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, or apparatus comprising the element. In this article, what each embodiment focuses on can be the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, the relevant parts can refer to the description of the method part.

[0147] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner can depend on the specific application and design constraints of the technical solution. The technician can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The technician can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0148] In the embodiments disclosed in this article, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units can be merely a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect coupling or communication connection of devices or units can be in electrical, mechanical, or other forms. The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to implement this embodiment. Additionally, in the embodiments of the present disclosure, the various functional units can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit.

[0149] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to the embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the block can occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks can also occur in a different order than that disclosed in the description. Sometimes, there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, which can depend on the functions involved. Each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A selection method for screw chillers, characterized in that, including: Obtain the nominal refrigerating capacity Q nom and the load rate LOAD%; According to the nominal refrigerating capacity Q nom and the load factor LOAD%, determine the target refrigerating capacity Q of the unit; Determine the maximum refrigerating capacity Q of the unit max and the minimum refrigerating capacity Q min ; According to the target refrigerating capacity Q and the maximum refrigerating capacity Q max and the minimum refrigerating capacity Q min , determine the operating parameters of the compressor of the unit corresponding to the load rate LOAD%; Determine the output refrigerating capacity Q of the unit corresponding to the load rate LOAD% according to the operating parameters t .

2. The option selection method according to claim 1, wherein According to the target refrigerating capacity Q and the maximum refrigerating capacity Q max , the minimum refrigerating capacity Q min , the steps for determining the operating parameters of the compressor of the unit corresponding to the load rate LOAD% include: When Q max ≤ Q, the operating parameters of the compressor are determined as the maximum value of the target parameters; When Q < Q max , the operating parameters of the compressor are determined according to Q min and the number n of the compressors in the operating state; wherein the target parameter includes the operating frequency or the capacity adjustment state.

3. The option selection method according to claim 2, wherein According to Q min and the number n of compressors in the operating state, the steps for determining the operating parameters of the compressors include: When n = 1 and Q min ≤ Q < Q max , the operating parameters of the compressor are determined as: the product of the maximum value of the target parameter and Q b , where Q b = Q / Q max ; When n = 1 and Q < Q min , determine that the operating parameters of the compressor are the minimum of the target parameters.

4. The option selection method according to claim 2, wherein According to Q min and the number n of compressors in the running state, the steps for determining the operating parameters of the compressors include: When n≥2 and Q<Q min , control one of the n compressors to shut down and update the minimum refrigerating capacity Q min of the unit; Determine the operating parameters of the compressor according to the updated Q min and the updated n.

5. The option selection method according to claim 2, wherein According to Q min and the number n of compressors in the running state, the steps for determining the operating parameters of the compressors include: When n ≥ 2 and Q min ≤ Q < Q max , determine the ratio of the absolute value of the difference between Q t and Q to Q; When the ratio is less than the ratio threshold and Q < Q max , save the performance parameters of the unit corresponding to the load rate LOAD% determined according to Q t ; and Control one of the n compressors to shut down and update Q max ; and According to the updated Q max , update the operating parameters of the compressor.

6. The selection method according to claim 5, characterized in that When the ratio is less than the ratio threshold and Q≥Q max , output the performance parameters of the unit corresponding to the load factor LOAD% determined according to Q t . when the ratio is greater than the ratio threshold, adjust the operating parameters; Update Q according to the adjusted operating parameters t .

7. The option selection method according to any one of claims 1 to 6, characterized in that, The step of obtaining the load rate LOAD% includes: determine the combination set of the load rates LOAD% participating in the calculation; obtain the load rates LOAD% in the combination set in sequence according to the preset order.

8. The option selection method according to claim 7, characterized in that The step of determining the combination set of the load rates LOAD% participating in the calculation includes: obtain multiple load rates LOAD% at preset interval differences between 0 and 100% to obtain a combination set including multiple load rates LOAD%.

9. A selection device for a screw chiller, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute the selection method for the screw chiller according to any one of claims 1 to 8 when running the program instructions.

10. A computer-readable storage medium storing program instructions, characterized in that, When running, the program instructions are used to cause the computer to execute the selection method for the screw chiller according to any one of claims 1 to 8.

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